1. Field of the Invention
The invention is in the field of bone prostheses.
2. Description of the Prior Art
In the past, many types of joint prostheses have been proposed. Among these are "ball-and-socket" joints, many of which include means for limiting the motion of the joint components relative to one another to essentially a single plane. Such "ball-and-socket" joints may be found in U.S. Pat. Nos. 3,760,427 to Schultz; 3,694,821 to Moritz; 3,651,521 to Devas; 3,638,243 to Campbell et al.; and 3,506,982 to Steffee. The Campbell and Devas joint prostheses are particularly described for use as elbow joint prostheses. Neither of these prostheses utilize a hinge pin to provide positive hinged motion and component retention. The Campbell prosthesis includes provision for axial rotational motion of the joint components relative to one another through freedom of the stem of the ball member to rotate partially in the slot of the socket member.
Various hinged elbow prostheses have also been proposed, relying upon the hinge pin for load bearing and not permitting any appreciable degree of "wobble" or rocking movement of one joint component relative to the other. Such joint prostheses are disclosed in U.S. Pat. Nos. 3,816,854 to Schlein; 3,772,709 to Swanson; 3,708,805 to Scales et al.; and 3,656,186 to Dee. Many of these prostheses are large and require resection of large parts of the natural joint. In such cases, any subsequently required prostheses of the same joint may be difficult or impossible.